diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
index bd57f402966..f35534cc703 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
@@ -416,7 +416,7 @@ public class DataNode extends ReconfigurableBase
 
   private ScheduledThreadPoolExecutor metricsLoggerTimer;
 
-  private final long startTime = now();
+  private long startTime = 0;
 
   /**
    * Creates a dummy DataNode for testing purpose.
@@ -2681,6 +2681,7 @@ public class DataNode extends ReconfigurableBase
     }
     ipcServer.setTracer(tracer);
     ipcServer.start();
+    startTime = now();
     startPlugins(getConf());
   }
 
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeMXBean.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeMXBean.java
index f72f1bce130..ea43cccbb18 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeMXBean.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/TestDataNodeMXBean.java
@@ -77,6 +77,7 @@ public class TestDataNodeMXBean extends SaslDataTransferTestCase {
       Assert.assertEquals(datanode.getVersion(),version);
       // get attribute "DNStartedTimeInMillis"
       long startTime = (long) mbs.getAttribute(mxbeanName, "DNStartedTimeInMillis");
+      Assert.assertTrue("Datanode start time should not be 0", startTime > 0);
       Assert.assertEquals(datanode.getDNStartedTimeInMillis(), startTime);
       // get attribute "SotfwareVersion"
       String softwareVersion =